Magnetic tape recording apparatus and method, magnetic tape format, and recording medium therefor

ABSTRACT

139 sync blocks, each having 111 bytes, are disposed on each track of a magnetic tape. Among the 139 sync blocks, 121 sync blocks each consist of a two-byte detection pattern for detecting the sync block, three-byte identification information for identifying the sync block, 96-byte main data, and 10-byte inner error correcting code added to the identification information and the main data. In the remaining 18 sync blocks, instead of the main data, 96-byte outer error correcting code is included. The outer error correcting code is provided for each group of the 139 sync blocks. Such a group of 139 sync blocks is obtained by dividing 2224 sync blocks contained in sixteen tracks by sixteen planes, 1668 sync blocks contained in twelve tracks by twelve planes, or 1112 sync blocks contained in eight tracks by eight planes. The sync blocks are arranged on the magnetic tape so that the distance between the sync blocks belonging to the identical plane is constant among the planes.

This application is a continuation of U.S. Application Ser. No.09/818,402, filed Mar. 27, 2001 now U.S. Pat. No. 6,996,330, which ishereby incorporated by reference in its entirety herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to magnetic tape recordingapparatuses and methods and magnetic tape formats, and to recordingmedia therefor. More specifically, the invention relates to a magnetictape recording apparatus and method for recording or readinghigh-quality video data on or from magnetic tape. The invention alsorelates to a magnetic tape format for use in the above-describedmagnetic tape recording apparatus and method and to a recording mediumfor storing a program implementing the above-described method.

2. Description of the Related Art

Along with advanced compression techniques, video data can be compressedand recorded on magnetic tape according to the digital video (DV)system. The format for use in the DV system is defined as a DV format ofconsumer digital video cassette recorders.

FIG. 1 illustrates the configuration of one track of a related DVformat. In the DV format, video data is recorded after being subjectedto 24-25 conversion. The numbers of bits shown in FIG. 1 representnumbers after 24-25 conversion has been performed on the video data.

The length of one track is substantially equal to a portion of magnetictape up to a winding angle of 174 degrees. Outside the one-trackportion, a 1250-bit overwrite margin is formed for preventing data fromremaining recorded.

The length of one track is 134975 bits when a rotary head is rotated insynchronization with a frequency of 60×1000/1001 Hz, and is 134850 bitswhen the rotary head is rotated in synchronization with a frequency of60 Hz.

In the one-track portion, an insert and track information (ITI) sector,an audio sector, a video sector, and a subcode sector are sequentiallydisposed in the tracing direction of the rotary head (from the left toright in FIG. 1). A gap G1 is formed between the ITI sector and theaudio sector, a gap G2 is formed between the audio sector and the videosector, and a gap G3 is formed between the video sector and the subcodesector.

The length of the ITI sector is 3600 bits. In the ITI sector, a 1400-bitpreamble for generating a clock, a start sync area (SSA), and a trackinformation area (TIA) (1920 bits in total are assigned to the SSA andthe TIA) are sequentially disposed. In the SSA, the bit string (syncnumber) required for detecting the position of the TIA is indicated. Inthe TIA, information indicating whether the format is a consumer DVformat and whether the format is an SP mode or an LP mode, andinformation concerning the pattern of a one-frame pilot signal isrecorded. After the TIA, a 280-bit postamble is disposed. The length ofthe gap G1 is 625 bits.

The length of the audio sector is 11550 bits. The first 400 bits and thelast 500 bits serve as a preamble and a postamble, respectively, and theremaining 10650 bits between the preamble and the postamble is used asaudio data. The length of the gap G2 is 700 bits.

The length of the video sector is 113225 bits. The first 400 bits andthe last 925 bits serve as a preamble and a postamble, respectively, andthe remaining 111900 bits between the preamble and the postamble areused as video data. The length of the gap G3 is 1550 bits.

The length of the subcode sector is 3725 bits when the rotary head isrotated at a frequency of 60×1000/1001 Hz, and is 3600 bits when therotary head is rotated at a frequency of 60 Hz. The first 1200 bits andthe last 1325 bits or 1200 bits (depending on the frequency of therotary head as discussed above) serve as a preamble and a postamble,respectively, and the remaining 1200 bits between the preamble and thepostamble are used as subcode data.

FIG. 2 illustrates the configuration of the video sector shown inFIG. 1. The video sector is formed of 149 90-byte sync blocks, as shownin FIG. 2. Among the 149 sync blocks, 138 sync blocks are formed of atwo-byte sync, a three-byte ID, 77-byte video data, and parity C1 (innererror correcting code). In the remaining 11 sync blocks, 77-byte parityC2 (outer error correcting code) is substituted for the video data.

In the DV format, not only the provision of the gaps G1, G2, and G3, butalso a preamble and a postamble are formed for each sector. That is, theso-called “overhead” is large, and a sufficient recording rate cannot beobtained for the real data.

About 25 Mbps are required for recording high-quality video data(hereinafter referred to as “high definition (HD) video data”). In theabove-described recording format, however, only 24 Mbps are ensured forthe data compressed by the main profile/high level (MP@HL) method in theMPEG system, except for search image data. As a result, althoughstandard-quality video data (hereinafter referred to as the “standarddefinition (SD) video data”) can be recorded, HD video data cannot berecorded after being compressed with the MP@HL or MP@H-14 method.

Additionally, the MPEG method is becoming mainstream for compressingvideo data. The unit of transport stream (TS) packets of theMPEG-compressed video data is 188 bytes. To dispose such a transportpacket in the synch blocks of the video sector shown in FIG. 2, threesync blocks are required, since each sync block is 77 bytes, (231 bytes(=77 bytes×three sync blocks)), thereby causing a redundancy of 43bytes. Thus, each sync block has about 14 redundancy bytes.

In this manner, according to the DV format, transport packets cannot beefficiently recorded.

SUMMARY OF THE INVENTION

Accordingly, in view of the above background, it is an object of thepresent invention to efficiently record transport packets.

In order to achieve the above object, according to one aspect of thepresent invention, there is provided a magnetic tape recording apparatusfor recording digital data on tracks of a magnetic tape by using arotary head. The magnetic tape recording apparatus includes a formattingunit for adding error correcting code to each of first group dataincluding video data, audio data, or search data, and second group dataincluding subcode data related to the first group data, and forformatting the first group data and the second group data so that theyare continuously disposed on the tracks of the magnetic tape. A supplyunit supplies the data formatted by the formatting unit to the rotaryhead so as to record the data on the magnetic tape. The formatting unitcontinuously disposes 139 sync blocks on each of the tracks, each of the139 sync blocks having 111 bytes. Among the 139 sync blocks, 121 syncblocks each consist of a two-byte detection pattern for detecting thesync block, three-byte identification information for identifying thesync block, 96-byte main data, and 10-byte inner error correcting codeadded to the identification information and the main data, and theremaining 18 sync blocks each consist of the two-byte detection pattern,the three-byte identification information, 96-byte outer errorcorrecting code, and the 10-byte inner error correcting code. The outererror correcting code is provided for each group of the 139 sync blocksobtained by dividing 2224 sync blocks contained in sixteen tracks bysixteen planes, 1668 sync blocks contained in twelve tracks by twelveplanes, or 1112 sync blocks contained in eight tracks by eight planes.The sync blocks are arranged on the magnetic tape so that the distancebetween the sync blocks belonging to the identical plane is constantamong the planes.

According to another aspect of the present invention, there is provideda magnetic tape recording method for use in a magnetic tape recordingapparatus for recording digital data on tracks of a magnetic tape byusing a rotary head. The magnetic tape recording method includes: aformatting step of adding error correcting code to each of first groupdata including video data, audio data, or search data, and second groupdata including subcode data related to the first group data, andformatting the first group data and the second group data so that theyare continuously disposed on the tracks of the magnetic tape; and asupply step of supplying the data formatted in the formatting step tothe rotary head so as to record the data on the magnetic tape. Theformatting step continuously disposes 139 sync blocks on each of thetracks, each of the 139 sync blocks having 111 bytes. Among the 139 syncblocks, 121 sync blocks each consist of a two-byte detection pattern fordetecting the sync block, three-byte identification information foridentifying the sync block, 96-byte main data, and 10-byte inner errorcorrecting code added to the identification information and the maindata, and the remaining 18 sync blocks each consist of the two-bytedetection pattern, the three-byte identification information, 96-byteouter error correcting code, and the 10-byte inner error correctingcode. The outer error correcting code is provided for each group of the139 sync blocks obtained by dividing 2224 sync blocks contained insixteen tracks by sixteen planes, 1668 sync blocks contained in twelvetracks by twelve planes, or 1112 sync blocks contained in eight tracksby eight planes. The sync blocks are arranged on the magnetic tape sothat the distance between the sync blocks belonging to the identicalplane is constant among the planes.

According to still another aspect of the present invention, there isprovided a recording medium for storing a computer readable program forallowing a magnetic tape recording apparatus to record digital data ontracks of a magnetic tape by using a rotary head. The computer readableprogram includes: a formatting step of adding error correcting code toeach of first group data including video data, audio data, or searchdata, and second group data including subcode data related to the firstgroup data, and formatting the first group data and the second groupdata so that they are continuously disposed on the tracks of themagnetic tape; and a supply step of supplying the data formatted in theformatting step to the rotary head so as to record the data on themagnetic tape. The formatting step continuously disposes 139 sync blockson each of the tracks, each of the 139 sync blocks having 111 bytes.Among the 139 sync blocks, 121 sync blocks each consist of a two-bytedetection pattern for detecting the sync block, three-byteidentification information for identifying the sync block, 96-byte maindata, and 10-byte inner error correcting code added to theidentification information and the main data, and the remaining 18 syncblocks each consist of the two-byte detection pattern, the three-byteidentification information, 96-byte outer error correcting code, and the10-byte inner error correcting code. The outer error correcting code isprovided for each group of the 139 sync blocks obtained by dividing 2224sync blocks contained in sixteen tracks by sixteen planes, 1668 syncblocks contained in twelve tracks by twelve planes, or 1112 sync blockscontained in eight tracks by eight planes. The sync blocks are arrangedon the magnetic tape so that the distance between the sync blocksbelonging to the identical plane is constant among the planes.

According to a further aspect of the present invention, there isprovided a format of a magnetic tape having tracks on which digital datais recorded by using a rotary head. The format includes error correctingcode added to each of first group data including video data, audio data,or search data, and second group data including subcode data related tothe first group data. The first group data and the second group data areformatted so that they are continuously disposed on the tracks of themagnetic tape. 139 sync blocks, each of the 139 sync blocks having 111bytes, are disposed on each of the tracks. Among the 139 sync blocks,121 sync blocks each consist of a two-byte detection pattern fordetecting the sync block, three-byte identification information foridentifying the sync block, 96-byte main data, and 10-byte inner errorcorrecting code added to the identification information and the maindata, and the remaining 18 sync blocks each consist of the two-bytedetection pattern, the three-byte identification information, 96-byteouter error correcting code, and the 10-byte inner error correctingcode. The outer error correcting code is provided for each group of the139 sync blocks obtained by dividing 2224 sync blocks contained insixteen tracks by sixteen planes, 1668 sync blocks contained in twelvetracks by twelve planes, or 1112 sync blocks contained in eight tracksby eight planes. The sync blocks are arranged on the magnetic tape sothat the distance between the sync blocks belonging to the identicalplane is constant among the planes.

According to a yet further aspect of the present invention, there isprovided a magnetic tape recording apparatus for recording digital dataon tracks of a magnetic tape by using a rotary head. The magnetic taperecording apparatus includes a formatting unit for adding errorcorrecting code to each of first group data including video data, audiodata, or search data, and second group data including subcode datarelated to the first group data, and for formatting the first group dataand the second group data so that they are continuously disposed on thetracks of the magnetic tape. A supply unit supplies the data formattedby the formatting unit to the rotary head so as to record the data onthe magnetic tape. The formatting unit continuously disposes 141 syncblocks on each of the tracks, each of the 141 sync blocks having 111bytes. Among the 141 sync blocks, 123 sync blocks each consist of atwo-byte detection pattern for detecting the sync block, three-byteidentification information for identifying the sync block, 96-byte maindata, and 10-byte inner error correcting code added to theidentification information and the main data, and the remaining 18 syncblocks each consist of the two-byte detection pattern, the three-byteidentification information, 96-byte outer error correcting code, and the10-byte inner error correcting code. The outer error correcting code isprovided for each group of the 141 sync blocks obtained by dividing 2256sync blocks contained in sixteen tracks by sixteen planes, 1692 syncblocks contained in twelve tracks by twelve planes, or 1128 sync blockscontained in eight tracks by eight planes. The sync blocks are arrangedon the magnetic tape so that the distance between the sync blocksbelonging to the identical plane is constant among the planes.

According to a further aspect of the present invention, there isprovided a magnetic tape recording method for use in a magnetic taperecording apparatus for recording digital data on tracks of a magnetictape by using a rotary head. The magnetic tape recording methodincludes: a formatting step of adding error correcting code to each offirst group data including video data, audio data, or search data, andsecond group data including subcode data related to the first groupdata, and formatting the first group data and the second group data sothat they are continuously disposed on the tracks of the magnetic tape;and a supply step of supplying the data formatted in the formatting stepto the rotary head so as to record the data on the magnetic tape. Theformatting step continuously disposes 141 sync blocks on each of thetracks, each of the 141 sync blocks having 111 bytes. Among the 141 syncblocks, 123 sync blocks each consist of a two-byte detection pattern fordetecting the sync block, three-byte identification information foridentifying the sync block, 96-byte main data, and 10-byte inner errorcorrecting code added to the identification information and the maindata, and the remaining 18 sync blocks each consist of the two-bytedetection pattern, the three-byte identification information, 96-byteouter error correcting code, and the 10-byte inner error correctingcode. The outer error correcting code is provided for each group of the141 sync blocks obtained by dividing 2256 sync blocks contained insixteen tracks by sixteen planes, 1692 sync blocks contained in twelvetracks by twelve planes, or 1128 sync blocks contained in eight tracksby eight planes. The sync blocks are arranged on the magnetic tape sothat the distance between the sync blocks belonging to the identicalplane is constant among the planes.

According to a further aspect of the present invention, there isprovided a recording medium for storing a computer readable programwhich allows a magnetic tape recording apparatus to record digital dataon tracks of a magnetic tape by using a rotary head. The computerreadable program includes: a formatting step of adding error correctingcode to each of first group data including video data, audio data, orsearch data, and second group data including subcode data related to thefirst group data, and formatting the first group data and the secondgroup data so that they are continuously disposed on the tracks of themagnetic tape; and a supply step of supplying the data formatted in theformatting step to the rotary head so as to record the data on themagnetic tape. The formatting step continuously disposes 141 sync blockson each of the tracks, each of the 141 sync blocks having 111 bytes.Among the 141 sync blocks, 123 sync blocks each consist of a two-bytedetection pattern for detecting the sync block, three-byteidentification information for identifying the sync block, 96-byte maindata, and 10-byte inner error correcting code added to theidentification information and the main data, and the remaining 18 syncblocks each consist of the two-byte detection pattern, the three-byteidentification information, 96-byte outer error correcting code, and the10-byte inner error correcting code. The outer error correcting code isprovided for each group of the 141 sync blocks obtained by dividing 2256sync blocks contained in sixteen tracks by sixteen planes, 1692 syncblocks contained in twelve tracks by twelve planes, or 1128 sync blockscontained in eight tracks by eight planes. The sync blocks are arrangedon the magnetic tape so that the distance between the sync blocksbelonging to the identical plane is constant among the planes.

According to a further aspect of the present invention, there isprovided a format of a magnetic tape having tracks on which digital datais recorded by using a rotary head. The format includes error correctingcode added to each of first group data including video data, audio data,or search data, and second group data including subcode data related tothe first group data. The first group data and the second group data areformatted so that they are continuously disposed on the tracks of themagnetic tape. The 141 sync blocks, each of the 141 sync blocks having111 bytes, are continuously disposed on each of the tracks. Among the141 sync blocks, 123 sync blocks each consist of a two-byte detectionpattern for detecting the sync block, three-byte identificationinformation for identifying the sync block, 96-byte main data, and10-byte inner error correcting code added to the identificationinformation and the main data, and the remaining 18 sync blocks eachconsist of the two-byte detection pattern, the three-byte identificationinformation, 96-byte outer error correcting code, and the 10-byte innererror correcting code: The outer error correcting code is provided foreach group of the 141 sync blocks obtained by dividing 2256 sync blockscontained in sixteen tracks by sixteen planes, 1692 sync blockscontained in twelve tracks by twelve planes, or 1128 sync blockscontained in eight tracks by eight planes. The sync blocks are arrangedon the magnetic tape so that the distance between the sync blocksbelonging to the identical plane is constant among the planes.

According to a further aspect of the present invention, there isprovided a magnetic tape recording apparatus for recording digital dataon tracks of a magnetic tape by using a rotary head. The magnetic taperecording apparatus includes a formatting unit for adding errorcorrecting code to each of first group data including video data, audiodata, or search data, and second group data including subcode datarelated to the first group data, and for formatting the first group dataand the second group data so that they are continuously disposed on thetracks of the magnetic tape. A supply unit supplies the data formattedby the formatting unit to the rotary head so as to record the data onthe magnetic tape. The formatting unit continuously disposes 135 syncblocks on each of the tracks, each of the 135 sync blocks having 114bytes. Among the 135 sync blocks, 118 sync blocks each consist of atwo-byte detection pattern for detecting the sync block, three-byteidentification information for identifying the sync block, 99-byte maindata, and 10-byte inner error correcting code added to theidentification information and the main data, and the remaining 17 syncblocks each consist of the two-byte detection pattern, the three-byteidentification information, 99-byte outer error correcting code, and the10-byte inner error correcting code. The outer error correcting code isprovided for each group of the 135 sync blocks obtained by dividing 2160sync blocks contained in sixteen tracks by sixteen planes, 1620 syncblocks contained in twelve tracks by twelve planes, or 1080 sync blockscontained in eight tracks by eight planes. The sync blocks are arrangedon the magnetic tape so that the distance between the sync blocksbelonging to the identical plane is constant among the planes.

According to a further aspect of the present invention, there isprovided a magnetic tape recording method for use in a magnetic taperecording apparatus for recording digital data on tracks of a magnetictape by using a rotary head. The magnetic tape recording methodincludes: a formatting step of adding error correcting code to each offirst group data including video data, audio data, or search data, andsecond group data including subcode data related to the first groupdata, and formatting the first group data and the second group data sothat they are continuously disposed on the tracks of the magnetic tape;and a supply step of supplying the data formatted in the formatting stepto the rotary head so as to record the data on the magnetic tape. Theformatting step continuously disposes 135 sync blocks on each of thetracks, each of the 135 sync blocks having 114 bytes. Among the 135 syncblocks, 118 sync blocks each consist of a two-byte detection pattern fordetecting the sync block, three-byte identification information foridentifying the sync block, 99-byte main data, and 10-byte inner errorcorrecting code added to the identification information and the maindata, and the remaining 17 sync blocks each consist of the two-bytedetection pattern, the three-byte identification information, 99-byteouter error correcting code, and the 10-byte inner error correctingcode. The outer error correcting code is provided for each group of the135 sync blocks obtained by dividing 2160 sync blocks contained insixteen tracks by sixteen planes, 1620 sync blocks contained in twelvetracks by twelve planes, or 1080 sync blocks contained in eight tracksby eight planes. The sync blocks are arranged on the magnetic tape sothat the distance between the sync blocks belonging to the identicalplane is constant among the planes.

According to a further aspect of the present invention, there isprovided a recording medium for storing a computer readable programwhich allows a magnetic tape recording apparatus to record digital dataon tracks of a magnetic tape by using a rotary head. The computerreadable program includes: a formatting step of adding error correctingcode to each of first group data including video data, audio data, orsearch data, and second group data including subcode data related to thefirst group data, and formatting the first group data and the secondgroup data so that they are continuously disposed on the tracks of themagnetic tape; and a supply step of supplying the data formatted in theformatting step to the rotary head so as to record the data on themagnetic tape. The formatting step continuously disposes 135 sync blockson each of the tracks, each of the 135 sync blocks having 114 bytes.Among the 135 sync blocks, 118 sync blocks each consist of a two-bytedetection pattern for detecting the sync block, three-byteidentification information for identifying the sync block, 99-byte maindata, and 10-byte inner error correcting code added to theidentification information and the main data, and the remaining 17 syncblocks each consist of the two-byte detection pattern, the three-byteidentification information, 99-byte outer error correcting code, and the10-byte inner error correcting code. The outer error correcting code isprovided for each group of the 135 sync blocks obtained by dividing 2160sync blocks contained in sixteen tracks by sixteen planes, 1620 syncblocks contained in twelve tracks by twelve planes, or 1080 sync blockscontained in eight tracks by eight planes. The sync blocks are arrangedon the magnetic tape so that the distance between the sync blocksbelonging to the identical plane is constant among the planes.

According to a further aspect of the present invention, there isprovided a format of a magnetic tape having tracks on which digital datais recorded by using a rotary head. The format includes error correctingcode added to each of first group data including video data, audio data,or search data, and second group data including subcode data related tothe first group data. The first group data and the second group data areformatted so that they are continuously disposed on the tracks of themagnetic tape. 135 sync blocks, each of the 135 sync blocks having 114bytes, are continuously disposed on each of the tracks. Among the 135sync blocks, 118 sync blocks each consist of a two-byte detectionpattern for detecting the sync block, three-byte identificationinformation for identifying the sync block, 99-byte main data, and10-byte inner error correcting code added to the identificationinformation and the main data, and the remaining 17 sync blocks eachconsist of the two-byte detection pattern, the three-byte identificationinformation, 99-byte outer error correcting code, and the 10-byte innererror correcting code. The outer error correcting code is provided foreach group of the 135 sync blocks obtained by dividing 2160 sync blockscontained in sixteen tracks by sixteen planes, 1620 sync blockscontained in twelve tracks by twelve planes, or 1080 sync blockscontained in eight tracks by eight planes. The sync blocks are arrangedon the magnetic tape so that the distance between the sync blocksbelonging to the identical plane is constant among the planes.

According to a further aspect of the present invention, there isprovided a magnetic tape recording apparatus for recording digital dataon tracks of a magnetic tape by using a rotary head. The magnetic taperecording apparatus includes a formatting unit for adding errorcorrecting code to each of first group data including video data, audiodata, or search data, and second group data including subcode datarelated to the first group data, and for formatting the first group dataand the second group data so that they are continuously disposed on thetracks of the magnetic tape. A supply unit supplies the data formattedby the formatting unit to the rotary head so as to record the data onthe magnetic tape. The formatting unit continuously disposes 135 syncblocks on each of the tracks, each of the 135 sync blocks having 114bytes. Among the 135 sync blocks, 118 sync blocks each consist of atwo-byte detection pattern for detecting the sync block, three-byteidentification information for identifying the sync block, 97-byte maindata, and 12-byte inner error correcting code added to theidentification information and the main data, and the remaining 17 syncblocks each consist of the two-byte detection pattern, the three-byteidentification information, 97-byte outer error correcting code, and the12-byte inner error correcting code. The outer error correcting code isprovided for each group of the 135 sync blocks obtained by dividing 2160sync blocks contained in sixteen tracks by sixteen planes, 1620 syncblocks contained in twelve tracks by twelve planes, or 1080 sync blockscontained in eight tracks by eight planes. The sync blocks are arrangedon the magnetic tape so that the distance between the sync blocksbelonging to the identical plane is constant among the planes.

According to a further aspect of the present invention, there isprovided a magnetic tape recording method for use in a magnetic taperecording apparatus for recording digital data on tracks of a magnetictape by using a rotary head. The magnetic tape recording methodcomprising: a formatting step of adding error correcting code to each offirst group data including video data, audio data, or search data, andsecond group data including subcode data related to the first groupdata, and formatting the first group data and the second group data sothat they are continuously disposed on the tracks of the magnetic tape;and a supply step of supplying the data formatted in the formatting stepto the rotary head so as to record the data on the magnetic tape. Theformatting step continuously disposes 135 sync blocks on each of thetracks, each of the 135 sync blocks having 114 bytes. Among the 135 syncblocks, 118 sync blocks each consist of a two-byte detection pattern fordetecting the sync block, three-byte identification information foridentifying the sync block, 97-byte main data, and 12-byte inner errorcorrecting code added to the identification information and the maindata, and the remaining 17 sync blocks each consist of the two-bytedetection pattern, the three-byte identification information, 97-byteouter error correcting code, and the 12-byte inner error correctingcode. The outer error correcting code is provided for each group of the135 sync blocks obtained by dividing 2160 sync blocks contained insixteen tracks by sixteen planes, 1620 sync blocks contained in twelvetracks by twelve planes, or 1080 sync blocks contained in eight tracksby eight planes. The sync blocks are arranged on the magnetic tape sothat the distance between the sync blocks belonging to the identicalplane is constant among the planes.

According to a further aspect of the present invention, there isprovided a recording medium for storing a computer readable programwhich allows a magnetic tape recording apparatus to record digital dataon tracks of a magnetic tape by using a rotary head. The computerreadable program includes: a formatting step of adding error correctingcode to each of first group data including video data, audio data, orsearch data, and second group data including subcode data related to thefirst group data, and formatting the first group data and the secondgroup data so that they are continuously disposed on the tracks of themagnetic tape; and a supply step of supplying the data formatted in theformatting step to the rotary head so as to record the data on themagnetic tape. The formatting step continuously disposes 135 sync blockson each of the tracks, each of the 135 sync blocks having 114 bytes.Among the 135 sync blocks, 118 sync blocks each consist of a two-bytedetection pattern for detecting the sync block, three-byteidentification information for identifying the sync block, 97-byte maindata, and 12-byte inner error correcting code added to theidentification information and the main data, and the remaining 17 syncblocks each consist of the two-byte detection pattern, the three-byteidentification information, 97-byte outer error correcting code, and the12-byte inner error correcting code. The outer error correcting code isprovided for each group of the 135 sync blocks obtained by dividing 2160sync blocks contained in sixteen tracks by sixteen planes, 1620 syncblocks contained in twelve tracks by twelve planes, or 1080 sync blockscontained in eight tracks by eight planes. The sync blocks are arrangedon the magnetic tape so that the distance between the sync blocksbelonging to the identical plane is constant among the planes.

According to a further aspect of the present invention, there isprovided a format of a magnetic tape having tracks on which digital datais recorded by using a rotary head. The format includes error correctingcode added to each of first group data including video data, audio data,or search data, and second group data including subcode data related tothe first group data. The first group data and the second group data areformatted so that they are continuously disposed on the tracks of themagnetic tape. 135 sync blocks, each of the 135 sync blocks having 114bytes, are continuously disposed on each of the tracks. Among the 135sync blocks, 118 sync blocks each consist of a two-byte detectionpattern for detecting the sync block, three-byte identificationinformation for identifying the sync block, 97-byte main data, and12-byte inner error correcting code added to the identificationinformation and the main data, and the remaining 17 sync blocks eachconsist of the two-byte detection pattern, the three-byte identificationinformation, 97-byte outer error correcting code, and the 12-byte innererror correcting code. The outer error correcting code is provided foreach group of the 135 sync blocks obtained by dividing 2160 sync blockscontained in sixteen tracks by sixteen planes, 1620 sync blockscontained in twelve tracks by twelve planes, or 1080 sync blockscontained in eight tracks by eight planes. The sync blocks are arrangedon the magnetic tape so that the distance between the sync blocksbelonging to the identical plane is constant among the planes.

In the aforementioned magnetic tape recording apparatus and method, therecording medium, and the magnetic tape format, the video data may behigh definition video data compressed by an MP@HL or MP@H-14 method.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the configuration of a track sector of a DV format;

FIG. 2 illustrates the configuration of a video sector shown in FIG. 1;

FIG. 3 is a block diagram illustrating an example of the configurationof a recording system for use in a magnetic tape recording/readingapparatus according to the present invention;

FIG. 4 illustrates the track format of magnetic tape shown in FIG. 3;

FIGS. 5, 6, and 7 illustrate tracking pilot signals to be recorded onthe track shown in FIG. 4;

FIG. 8 illustrates the sector arrangement of the track shown in FIG. 4;

FIG. 9 illustrates an example of an ITI preamble of track F0 shown inFIG. 8;

FIG. 10 illustrates an example of an ITI preamble of track F1 shown inFIG. 8;

FIG. 11 illustrates an example of an ITI preamble of track F2 shown inFIG. 8;

FIG. 12 illustrates an example of SSA data of track F0 shown in FIG. 8;

FIG. 13 illustrates an example of SSA data of track F1 shown in FIG. 8;

FIG. 14 illustrates an example of SSA data of track F2 shown in FIG. 8;

FIG. 15 illustrates the configuration of a sync block of a TIA shown inFIG. 8;

FIG. 16 illustrates track information of the TIA shown in FIG. 8;

FIG. 17 illustrates information represented by APT of the TIA shown inFIG. 8;

FIG. 18 illustrates an example of TIA data of track F0 shown in FIG. 8;

FIG. 19 illustrates an example of TIA data of track F1 shown in FIG. 8;

FIG. 20 illustrates an example of TIA data of track F2 shown in FIG. 8;

FIG. 21 illustrates an example of data of an ITI postamble of track F0shown in FIG. 8;

FIG. 22 illustrates an example of data of an ITI postamble of track F1shown in FIG. 8;

FIG. 23 illustrates an example of data of an ITI postamble of track F2shown in FIG. 8;

FIGS. 24A, 24B, and 24C illustrate an example of the configuration ofthe main sector shown in FIG. 8;

FIG. 25 illustrates the configuration of the subcode sector shown inFIG. 8;

FIG. 26 illustrates the pattern of the postamble shown in FIG. 8;

FIG. 27 is a block diagram illustrating an example of the configurationof a reading system for use in the magnetic tape recording/readingapparatus according to the present invention;

FIG. 28 illustrates the relationship between the length of a sync blockand the 24-25 conversion cycle;

FIG. 29 illustrates the configuration of error correcting codes of async block;

FIG. 30 illustrates the relationship between the bit error probabilityand the probability that data cannot be correctly decoded;

FIG. 31 illustrates the configuration of inner error correcting codes ofa sync block of the DV format;

FIG. 32 illustrates the parity configuration of the ID of the DV format;

FIG. 33 illustrates an example of the arrangement of sync blocks on aplurality of planes on magnetic tape;

FIG. 34 illustrates another example of the arrangement of sync blocks ona plurality of planes on magnetic tape;

FIG. 35 illustrates interleave processing when the order of the outputfrom a video data compressor is arranged to the order of sync blocks onmagnetic tape;

FIG. 36 illustrates interleave processing when the order of the outputfrom the video data compressor is arranged to the order of sync blockson the planes;

FIGS. 37, 38, and 39 illustrate the arrangement of sync blocks onmagnetic tape after being interleaved on 16 planes over 16 tracks andbeing provided with parities;

FIGS. 40, 41, and 42 illustrate the arrangement of sync blocks onmagnetic tape after being provided with parities and being interleavedon 16 planes over 16 tracks;

FIG. 43 illustrates the error resistance to damaged tracks caused byburst errors;

FIG. 44 illustrates the error resistance to damaged tracks on one sidechannel caused by burst errors;

FIGS. 45 and 46 illustrate the arrangement of sync blocks on magnetictape after being interleaved on 12 planes over 12 tracks and beingprovided with parities;

FIGS. 47 and 48 illustrate the arrangement of sync blocks on magnetictape after being interleaved on 8 planes over 8 tracks and beingprovided with parities;

FIGS. 49A, 49B, and 49C illustrate another example of the configurationof the main sector shown in FIG. 8;

FIG. 50 is a block diagram illustrating another example of theconfiguration of a recording system for use in a magnetic taperecording/reading apparatus according to the present invention;

FIG. 51 illustrates the track format of magnetic tape shown in FIG. 50;

FIG. 52 is a block diagram illustrating another example of theconfiguration of a reading system for use in the magnetic taperecording/reading apparatus according to the present invention;

FIGS. 53, 54, and 55 illustrate the arrangement of sync blocks onmagnetic tape after being interleaved on 16 planes over 16 tracks andbeing provided with parities;

FIGS. 56, 57, and 58 illustrate the arrangement of sync blocks onmagnetic tape after being provided with parities and being interleavedon 16 planes over 16 tracks;

FIGS. 59A, 59B, and 59C illustrate still another example of theconfiguration of the main sector shown in FIG. 8;

FIG. 60 illustrates an example of the sector arrangement of the trackshown in FIGS. 59A, 59B, and 59C;

FIGS. 61A, 61B, and 61C illustrate a further example of theconfiguration of the main sector shown in FIG. 8; and

FIG. 62 illustrates the relationship between the bit error probabilityand the probability that data cannot be correctly decoded.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3 illustrates the configuration of a recording system of a magnetictape recording/reading apparatus to which the present invention isapplied. A video data compressor 1 compresses input HD video signalsaccording to an MPEG method, such as MP@HL or MP@H-14. An audio datacompressor 2 compresses audio signals corresponding to the HD videosignals according to, for example, an audio compression methodcorresponding to a DV-format compression method. System data, such asauxiliary data or subcode data, is input into a terminal 3 from acontroller 13.

A switch 4 suitably selects one of the outputs from among the video datacompressor 1, the audio data compressor 2, and the terminal 3 under thecontrol of the controller 13, and supplies the selected output to anerror code/ID adder 5. The error code/ID adder 5 adds an errordetecting/correcting code or an ID to the input data and performsinterleave processing for 16 tracks. The error code/ID adder 5 thenoutputs the resulting data to a 24-25 converter 6. The 24–25 converter 6converts the data in units of 24 bits into data in units of 25 bits byadding one redundant bit, which is selected so that a pilot signal for atracking operation appears at the highest level.

A sync ITI generator 7 generates sync data to be added to main data(FIG. 24) or subcode (FIG. 25), preamble and postamble data, and ITIdata (FIG. 8).

A switch 8 selects one of the outputs from the 24-25 converter 6 and thesync ITI generator 7 under the control of the controller 13, andsupplies the selected output to a modulator 9. The modulator 9randomizes the input data so as to prevent “1”s or “0”s from beingconsecutive, and also modulates the data according to a method suitablefor recording the data on magnetic tape 21 (the same method as that usedfor the DV format). The modulator 9 then supplies the resulting signalto a parallel-to-serial (P/S) converter 10.

The P/S converter 10 converts the input parallel data into serial data.An amplifier 11 then amplifies the data input from the P/S converter 10.The amplified data is supplied to a rotary head 12 attached to a rotarydrum (not shown), and is then recorded on the magnetic tape 21.

FIG. 4 illustrates the format of tracks which are formed on the magnetictape 21 by the rotary head 12. The rotary head 12 traces over themagnetic tape 21 in the direction from the bottom right to the upperleft in the drawing so as to form tracks which tilt with respect to thelongitudinal direction of the magnetic tape 21. The magnetic tape 21 isconveyed from the right to the left direction in the drawing.

The tracks can be divided into F0, F1, and F2 according to the type ofpilot signal used for a tracking control operation to be recorded on thetracks. The tracks are formed in the order of F0, F1, F0, F2, F0, F1,F0, and F2.

In track F0, as shown in FIG. 5, neither a pilot signal at frequency f1nor a pilot signal at frequency f2 is recorded. In contrast, as shown inFIG. 6, in track F1, a pilot signal at frequency f1 is recorded. Intrack F2, as shown in FIG. 7, a pilot signal at frequency f2 isrecorded.

Frequencies f1 and f2 are respectively 1/90 and 1/60 of the recordingfrequency of a channel bit.

The depth of the notch at frequency f1 or f2 of track F0 is, as shown inFIG. 5, 9 dB. In contrast, the carrier-to-noise ratio (CNR) of the pilotsignal at frequency f1 or f2 is, as shown in FIG. 6 or 7, greater than16 dB and smaller than 19 dB. The depth of the notch at frequency f1 orf2 is greater than 3 dB.

The track pattern having the above-described frequency characteristicsis the same pattern used in the DV format. Accordingly, magnetic tape, arotary head, a driving system, a demodulation system, and a controlsystem for use in consumer digital video cassette recorders can beemployed in the present invention. The track pitch and the tape speedare similar to those in the DV format.

FIG. 8 illustrates an example of the sector arrangement in each track.The number of bits of the individual elements shown in FIG. 8 arenumbers after 24-25 conversion is performed on the data. The length ofone track is 134975 bits when the rotary head 12 is rotated at afrequency of 60×1000/1001 Hz, and is 134850 bits when the rotary head 12is rotated at a frequency of 60 Hz. The length of one track is equal toa portion of the magnetic tape 21 up to a winding angle of 174 degrees.After one track, a 1250-bit overwrite margin is formed for preventingdata from remaining recorded.

In FIG. 8, the rotary head 12 traces over the track from the left to theright. At the head of the track, a 3600-bit ITI sector, which is similarto the counterpart shown in FIG. 1, is disposed. At the start of the ITIsector, a 1400-bit ITI preamble is disposed. The ITI preamble of track 0has data, such as that shown in FIG. 9, and the ITI preamble of track 1has data, such as that shown in FIG. 10. The ITI preamble of track 2 hasdata, such as that shown in FIG. 11. Based on the data of the ITIpreamble, a clock is generated when the data is read from the magnetictape 21.

Subsequent to the ITI preamble, a 1830-bit SSA is located. The SSA oftrack F0 is formed of data, such as that shown in FIG. 12, the SSA oftrack F1 includes data, such as that shown in FIG. 13, and the SSA oftrack F2 contains data, such as that shown in FIG. 14. The start of thesubsequent TIA can be detected by the SSA.

The 90-bit TIA is positioned after the SSA. The TIA is formed of 30 syncblocks, and each block is formed of 30 bits ranging from b29 to b0, asshown in FIG. 15. The same data is recorded in three consecutive syncblocks. Accordingly, the same data is substantially repeated three timesin the TIA.

Among the 30 bits (bits b29 through b0), the data shown in FIG. 16 isdisposed for bits from b27 to b22, and bits from b17 to b12. That is,APT₂ is disposed in bits b12 and b13, APT₁ is positioned for bits 14 andb15, and APT₀ is positioned for bits 16 and b17.

The type of data recorded on the track in the DV format can beidentified by APT₂, APT₁, and APT₀. For example, when the values ofAPT₂, APT₁, and APT₀ are “000”, data for a consumer digital videocassette recorder, i.e., DV-format data, is recorded on the track. Whenthe values of APT₂, APT₁, and APT₀ are “111”, data is not recorded onthe track. Accordingly, when the values “111” are detected as APT₂,APT₁, and APT₀, a DV-format-compatible magnetic-tape recording/readingapparatus does not perform a reading operation.

In this embodiment, as shown in FIG. 16, the values “111” are recordedas APT₂, APT₁, and APT₀. As a result, when the magnetic tape 21 shown inFIG. 3 is read by a DV-format-compatible magnetic-tape readingapparatus, a recording operation is not performed. In contrast, when themagnetic tape 21 is read by a HD-signal-compatible magnetic-taperecording/reading apparatus, a reading operation is performed assumingthat HD video signal data is recorded on the magnetic tape 21

As shown in FIG. 16, TP₁ is recorded in bits b22 and b23, while TP₀ isrecorded in bits b24 and b25. In the DV format, when the values of TP₁and TP₀ are “11”, the track pitch is 0 for an SP mode pitch. When thevalues of TP₁ and TP₀ are “10”, the track pitch is 1 for an LP modepitch. When the values of TP₁ and TP₀ are “01”, the track pitch is 2.When the values of TP₁ and TP₀ are “00”, the track pitch is 3. In thepresent invention, the definition of TP₁ and TP₀ is similar to that inthe DV format.

In the example shown in FIG. 16, since TP₁ and TP₀ indicate “11”, the SPmode is selected.

PF₀ and PF₁ are recorded in bit b26 and b27, respectively. PF stands fora pilot frame, and 0 represents pilot frame 0, and 1 represents pilotframe 1. Pilot frame 0 indicates that track F1 is disposed after trackF0 as the first two tracks of the ten tracks forming one frame. Pilotframe 1 indicates that track F2 is disposed after track F0 as theabove-described first two tracks.

That is, as discussed with reference to FIG. 4, tracks are formed in theorder of F0, F1, F0, F2, F0, F1, F0, and F2. If the first two tracks ofone predetermined frame are F0 and F1, the subsequent two tracks can beF0 and F1 or F0 and F2 according to the amount of data of the previousframe. The type of track pattern, i.e., F0 and F1 or F0 and F2, can berepresented by the pilot frame.

As stated above, the bits of the TIA sync blocks are randomized so as toprevent a considerably large number of consecutive “1”s or “0”s fromoccurring. As a result, the TIA data formed of three sync blocks (90bits), each having bits b29 through b0 shown in FIG. 15, of track F0 canbe indicated as shown in FIG. 18. The TIA data of track F1 can berepresented as shown in FIG. 19, and the TIA data of track F2 can bedesignated as shown in FIG. 20.

After the TIA, as shown in FIG. 8, a 280-bit postamble is disposed. Thepostamble of track 0 can be indicated as shown in FIG. 21, the postambleof track 1 can be represented as shown in FIG. 22, and the postamble oftrack 2 can be indicates as shown in FIG. 23. The data of the ITI sectoris generated by the sync ITI generator 7.

After the postamble, a 128575-bit main sector is disposed. The structureof the main sector is shown in FIG. 24A.

The main sector is formed of, as shown in FIG. 24A, 139 sync blocks, andeach sync block has 888 bits (111 bytes). The first 121 sync blocks eachhave a 16-bit sync, a 24-bit ID, an eight-bit header, 760-bit main data,and 80-bit parity C1. The sync is generated by the sync ITI generator 7.The ID is added by the error code/ID adder 5. The header includes IDinformation indicating whether the main data is audio data, video data,search video data, transport stream data, or auxiliary data. The headerdata is supplied as one type of system data from the controller 13 viathe terminal 3.

If the main data is video data, it is supplied from the video datacompressor 1. If the main data is audio data, it is supplied from theaudio data compressor 2. If the main data is auxiliary data, it issupplied from the controller 13 via the terminal 3.

The parity C1 is calculated for each sync block from the ID, the header,and the main data by the error code/ID adder 5.

Among the 139 sync blocks, the last 18 sync blocks are formed of thesync, the ID, parity C2, and parity C1. Parity C2 can be calculatedbased on the header or the main data in the longitudinal direction inFIG. 24A. This calculation is performed in the error code/ID adder 5.

The total amount of the data of the main sector is 888 bits×139 syncblocks=123432 bits, and becomes 128575 bits after 24-25 conversion. Themaximum data rate when the rotary head 12 is rotated in synchronizationwith 60 Hz is substantially 760 bits×121 sync blocks×10 tracks×30Hz=27.588 Mbps. This bit rate is sufficient to record MP@HL-compressedor MP@H-14-compressed HD video data, audio compressed data, auxiliarydata, and search video data.

Subsequent to the main data, a 1250-bit subcode sector is disposed. Theconfiguration of the subcode sector is shown in FIG. 25.

A one-track subcode sector is formed of 10 subcode sync blocks, and eachsubcode sync block is formed of a sync, an ID, subcode data, and aparity.

At the head of each subcode sync block of the 1250-bit (after 24-25conversion) subcode sector, a 16-bit sync (before 24-25 conversion) isdisposed, followed by a 24-bit ID. The sync is generated by the sync ITIgenerator 7, and the ID is added by the error code/ID adder 5.

After the ID, 40-bit subcode data is located. The subcode data issupplied from the controller 13 via the terminal 3, and includes, forexample, a track number and a time code number. Subsequent to thesubcode data, a 40-bit parity is added. The parity is added by the errorcode/ID adder 5.

The 120-bit subcode sync block data before 24-25 conversion becomes125-bit (=120×25/24) data after 24-25 conversion.

After the subcode sector, a postamble is disposed. In the postamble, acombination of pattern A and pattern B required for generating a clock,for example, that shown in FIG. 26, is recorded. Pattern B has “1”s and“0”s inverted with respect to those of pattern A, and vice versa. Bysuitably combining pattern A and pattern B, the tracking patterns F0,F1, and F2 shown in FIGS. 5, 6, and 7, respectively, can be implemented.The run pattern shown in FIG. 9 represents a pattern after 24-25conversion is performed by the 24-25 converter 6 shown in FIG. 3. Thelength of the postamble is 1550 bits when the rotary head 12 is rotatedin synchronization with 60×1000/1001 Hz, and is 1425 bits when therotary head 12 is rotated in synchronization with 60 Hz.

The operation of the recording system shown in FIG. 3 is as follows. AHD video signal is input, together with search video data (thumbnaildata), into the video data compressor 1, and is compressed according to,for example, the MP@HL or MP@H-14 method. The audio signal is input intothe audio data compressor 2, and is compressed according to a methodsimilar to a DV-format-compatible method. System data, such as subcodedata, auxiliary data, and the header, is supplied to the terminal 3 fromthe controller 13.

Under the control of the controller 13, the switch 4 appropriatelyincorporates the video data (including the search video data) outputfrom the video data compressor 1, the audio data output from the audiodata compressor 2, and the system data output from the terminal 3, andcombines the above-described data and outputs it to the error code/IDadder 5.

The error code/ID adder 5 adds a 24-bit ID to each sync block of themain sector shown in FIG. 24A. The parity C1 shown in FIG. 24A iscalculated for each sync block and is added, and instead of the headerand the main data, the parity C2 is added to the last 18 sync blocks ofthe 139 sync blocks.

The error code/ID adder 5 also adds, as shown in FIG. 25, the 24-bit IDfor each subcode sync block of the subcode data, and also calculates the40-bit parity.

The error code/ID adder 5 retains 16 tracks of the main data andinterleaves it across 16 tracks (subcode data is not interleaved).

The 24-25 converter 6 converts data in units of 24 bits supplied fromthe error code/ID adder 5 into data in units of 25 bits. Accordingly,the tracking pilot signal components at frequencies f1 and f2 shown inFIGS. 5 through 7 appear at the highest level.

The sync ITI generator 7 adds, as shown in FIG. 24A, a 16-bit sync toeach sync block of the main sector. The sync ITI generator 7 also adds,as shown in FIG. 25, a 16-bit sync to each subcode sync block of thesubcode sector. Additionally, the ITI generator 7 generates the runpattern of the postamble shown in FIG. 26, and also generates the ITIsector data.

More specifically, the above-described data is added or combined asfollows. The controller 13 changes the switch 8 to select between thedata output from the sync ITI generator 7 and the data from the 24-25converter 6, and the switch 8 supplies the selected data to themodulator 9.

The modulator 9 randomizes the input data and also modulates itaccording to a DV-format-compatible method. The modulated data is thenoutput to the P/S converter 10. The P/S converter 10 converts the inputparallel data into serial data, and supplies it to the rotary head 12via the amplifier 11. The rotary head 12 records the input data on themagnetic tape 21.

FIG. 27 illustrates the configuration of a reading system for readingdata recorded on the magnetic tape 21 as discussed above.

The rotary head 12 reads the data recorded on the magnetic tape 21 andoutputs it to an amplifier 41. The amplifier 41 amplifies the inputsignal and supplies it to an analog-to-digital (A/D) converter 42. TheA/D converter 42 converts the input analog signal into a digital signaland supplies it to a demodulator 43. The demodulator 43 derandomizes thedata supplied from the A/D converter 42 according to a methodcorresponding to the randomization method employed by the modulator 9,and also demodulates the derandomized data according to a methodcorresponding to the modulation method employed by the modulator 9.

A sync ITI detector 44 detects a sync of each sync block of the mainsector shown in FIG. 24A, a sync of each subcode sync block of thesubcode sector shown in FIG. 25, and the ITI sector shown in FIG. 8 fromthe demodulated data output from the demodulator 43. The sync ITIdetector 44 then supplies the detected syncs to an error corrector/IDdetector 46. A 25-24 converter 45 converts the data in units of 25 bitssupplied from the demodulator 43 into data in units of 24 bits inaccordance with the 24-25 conversion performed by the 24-25 converter 6,and then outputs the converted data to the error detector/ID converter46.

The error corrector/ID converter 46 performs error correction, IDdetection, and interleave processing based on the syncs input from thesync ITI detector 44. Under the control of a controller 13, a switch 47outputs the video data (including search video data) to a video datadecompressor 48, the audio data to an audio data decompressor 49, andsystem data, such as subcode data and auxiliary data, to the controller13 via a terminal 50.

The video data decompressor 48 decompresses the input video data andconverts the decompressed digital data into analog data, which is thenoutput as an analog HD video signal. The audio data decompressor 49decompresses the input audio data and converts the decompressed digitaldata into analog data, which is then output as an analog audio signal.

The reading operation of the reading system shown in FIG. 27 is asfollows. The rotary head 12 reads the data recorded on the magnetic tape21. The read data is then amplified by the amplifier 41 and is suppliedto the A/D converter 42. The analog data is converted into digital databy the A/D converter 42 and is input into the demodulator 43. Thedigital data is then derandomized and demodulated by the demodulator 43in accordance with a derandomization method and a demodulation methodcorresponding to the randomization method and the modulation method,respectively, performed by the modulator 9 shown in FIG. 3.

The output of the A/D converter 42 is also supplied to a servo circuit(not shown) in which pattern A and pattern B recorded in the postamble(FIG. 26) are read so as to generate a tracking pilot signal, therebyperforming the tracking control operation. It should be noted that thetracking control signal is read from the overall track, though atracking signal component read from the ITI sector appears at thehighest level.

The 25-24 converter 45 converts the demodulated data in units of 25 bitsinto data in units of 24 bits, and outputs it to the error corrector/IDdetector 46.

The sync ITI detector 44 detects the syncs of the main sector shown inFIG. 24A or the syncs of the subcode sector shown in FIG. 25 from thedata output from the demodulator 43, and supplies the detected syncs tothe error corrector/ID detector 46. The error corrector/ID detector 46stores 16 tracks of the main data and performs deinterleave processing,and also performs error correcting of the main data by using parities C1and C2 of the main sector shown in FIG. 24A. The error corrector/IDdetector 46 also detects the ID of the main sector and determineswhether the data recorded in each sync block is video data, audio data,auxiliary data, or search video data.

The error corrector/ID detector 46 also performs error correcting of thesubcode data by using the parity of the subcode sector shown in FIG. 25,and detects the ID so as to determine the type of subcode data, i.e.,whether the subcode data represents a track number or a time codenumber.

The switch 47 supplies the video data and the search video data to thevideo data decompressor 48 based on the ID detected by the errorcorrector/ID detector 46. The video data decompressor 48 decompressesthe data according to a decompression method corresponding to thecompression method employed by the video data compressor 1 shown in FIG.3, and outputs the decompressed data as the video signal.

The switch 47 outputs the audio data to the audio data decompressor 49.The audio data decompressor 49 decompresses the data according to adecompression method corresponding to the compression method employed bythe audio data compressor 2 shown in FIG. 3, and outputs thedecompressed data as the audio signal.

The switch 47 also outputs the auxiliary data and subcode data outputfrom the error corrector/ID detector 46 to the controller 13 via theterminal 50.

Details of the configuration of the main sector are further discussedbelow. As shown in FIG. 24A, each sync block of the main data has 111bytes (=888 bits) consisting of a two-byte sync pattern, a three-byteID, 96-byte main data, and 10-byte parity C1. The data length of thesync block after 24-25 conversion, i.e., 925 bits (=111×8×25/24) are amultiple of 25 bits, and also, 888 bits are a multiple of three bytes(24 bits). As a result, as shown in FIG. 28, the head of a sync blockcoincides with the start of a 24-25 conversion cycle, therebyfacilitating signal processing.

As the inner error correcting code, as shown in FIG. 29, a Galois fieldGF (2⁸) 109-byte Reed-Solomon code (109, 99, 11) is formed of athree-byte ID, 96-byte main data, and 10-byte parity C1. When the biterror probability of a read bit data string recorded on the magnetictape 21 is indicated by Pb, the Galois field GF (2⁸) symbol errorprobability P_(S) can be expressed by the following equation.P _(S)=1−(1−Pb)⁸

The probability P that the Reed-Solomon code cannot be correctly decoded(impossible to be decoded or is erroneously decoded) can be expressed bythe following equation.

$P = {1 - {\sum\limits_{i = 0}^{t}\;{{{}_{}^{}{}_{}^{}} \cdot \left( P_{s} \right)^{\; i} \cdot \left( {1 - P_{s}} \right)^{109 - i}}}}$

Curve A in FIG. 30 indicates the probability P that the Reed-Solomoncode cannot be correctly decoded.

For comparison with curve A, the probability that DV format data cannotbe correctly decoded is found. In the DV format, as shown in FIG. 31, asthe inner error correcting code, a Galois field (2⁸) Reed-Solomon code(85, 77, 9) is formed of 77-byte main data and 8-byte parity C1 withoutincluding the ID. The probability that the Reed-Solomon code cannot becorrectly decoded is expressed by curve B in FIG. 30.

Curve A obtained by the format of the main sector according to thepresent invention shows that the probability that Reed-Solomon codecannot be correctly decoded when the bit error probability is around0.0001 is about 1E-09. In contrast, curve B obtained by the DV formatreveals that the above-described probability is about 1E-08. Thus, theprobability P indicated by curve A is smaller than that of curve B byone and half orders of magnitude.

The probability Q that Reed-Solomon code is erroneously corrected issimply determined by the number of parity bits N and can be expressed bythe following equation.Q=1/2^(N)The number of parity bits in the DV format is 64 (=8×8), and theprobability that the Reed-Solomon data is erroneously corrected can beexpressed by the following expression.QDV=5.4E−20In contrast, the number of parity bits in the present invention is 80(=10×8), and the probability QIN that data is erroneously corrected canbe expressed by the following equation.QIN=8.3E−25That is, according to the present invention, the probability that theReed-Solomon code is erroneously corrected is reduced by about fiveorders of magnitudes over the DV format.

Additionally, in the present invention, the ID is included in the innererror correcting code, as shown in FIG. 29. Conversely, as shown in FIG.31, the ID is not included in the inner error correcting code.

In the DV format, the ID is error-corrected by two-planeBose-Chaudhuri-Hocquenghem (BCH) code (12, 8, 3). FIG. 32 illustrates IDparities in the DV format. Parities P₀ through P₇ are calculated fortwo-byte data C₀ through C₁₅, as shown in FIG. 32, resulting in theDV-format ID. In this error correcting, since the minimum Hammingdistance is three symbols, an error having three symbols may becorrected to a wrong code. Additionally, the BCH code is binary code,and the bit rate is merely arranged in the order of No good-OK-No good.Thus, the data may be erroneously corrected.

In contrast, according to the present invention, the three-byte ID isincluded together with the main data in the Reed-Solomon code, therebyimproving the error correcting performance. In terms of the ID, theReed-Solomon code is substituted for the BCD code, thereby increasingerror resistant characteristics compared to the DV format. In terms ofthe main data, the code length is increased, thereby enhancing thecoding efficiency.

By using a Galois field (2⁸) Reed-Solomon code (139, 121, 19), biterrors caused by a scratch extending a maximum of 650 μm in the trackingdirection can be corrected. Moreover, as will be discussed below, ifouter error correcting code is interleaved across a plurality of tracks,for example, 16 tracks, on the magnetic tape 21, errors continuouslyextending two tracks can be corrected.

Also, in the present invention, sync blocks used for error correction(sync blocks having parity C2) are disposed toward the front in thetracing direction of the rotary head 12 (in the direction from thebottom to up in FIG. 24A), i.e., at the head of the track. The head ofthe track is vulnerable to reading errors since it is frequently incontact with the rotary head 12. In the format shown in FIG. 24A,however, sync blocks having parity C2 are disposed at the head of thetrack, and sync blocks including the main data are disposed toward theend. As a result, the probability that the sync blocks having the maindata cannot be decoded can be lower than the probability that the syncblocks having parity C2 cannot be decoded.

Alternatively, as shown in FIG. 24B, parity C2 may be located at theuppermost portion (toward the end of the track).

Alternatively, as shown in FIG. 24C, parity C2 may be divided andlocated near the head and near the end of the track. In the exampleshown in FIG. 24C, 9 sync blocks having parity C2 are disposed near thehead of the track, and another 9 sync blocks having parity C2 arelocated near the end of the track. The split ratio of sync blocks havingparity C2 does not have to be 1:1, as shown in FIG. 24C.

In the present invention, for enhancing error resistance to a scratchextending over more than one track, error correcting codes are shuffledover a plurality of tracks, and are then recorded on the magnetic tape21. Accordingly, in N tracks, N-plane error correcting codes are formed.On one plane, Galois field GF (2⁸) Reed-Solomon codes (139, 121, 19) areused. On the magnetic tape 21, the distance between adjacent sync blocksbelonging to the same plane is fixed so that the resistance to a scratchextending in the longitudinal direction of the track can be consistentregardless of the location of the scratch in the tracking direction.

FIG. 33 illustrates an example of the arrangement of sync blocks on themagnetic tape 21 when error correcting codes are interleaved overeight-plane eight tracks. In this example, the first-plane througheighth-plane sync blocks are sequentially disposed in the top to bottomdirection from the leftmost track. After an eighth-plane sync block isdisposed, another first-plane sync block is positioned again. When async block is located at the bottommost portion of one track (in theexample shown in FIG. 33, when the 22nd sync block is disposed), thesubsequent-plane sync block is positioned at the uppermost portion of atrack right adjacent to the previous track. In this manner, sync blocksare disposed for the eight-plane eight tracks.

A sync block 81 and a sync block 82 belong to the same plane (secondplane), and are separated from each other by eight blocks. A sync block83 and a sync block 84 also belong to the same plane (first plane), andare also separated from each other by eight blocks. In this manner, thedistance between adjacent sync blocks belonging to the same plane isconstant.

In FIG. 33, it is assumed that a scratch 71 or 72 is formed in thelongitudinal direction (in the vertical direction in the drawing) forthe eight tracks. Such a scratch 71 or 72 extends over only 6 syncblocks for each track. Accordingly, only one sync block for each planeis missing, which can be sufficiently corrected.

That is, a scratch formed with the same length among the tracks (i.e.,the same height in FIG. 33) can be equally corrected with the sameresult regardless of where the scratch is formed on the track.

In the example shown in FIG. 33, the continuity of the planes betweenadjacent tracks is ensured. Thus, the error correcting performance canbe best exhibited for temporally continuous burst errors caused by anextraneous substance attached to the magnetic tape 21 or spontaneousclogging at spliced portions of the magnetic tape 21 caused during arecording operation.

FIG. 34 illustrates another example of the arrangement of sync blocks onthe magnetic tape 21 when error correcting codes are interleaved overeight-plane eight tracks. In this example, the arrangement of syncblocks is the same between two adjacent tracks. The first-plane througheighth-plane sync blocks are sequentially disposed from the top to thebottom of the two adjacent tracks, and when the sync blocks reach thebottommost portions of the tracks, the subsequent sync blocks arepositioned at the uppermost portions of the tracks, which are locatedtwo tracks away from the previous tracks.

According to the arrangement of the sync blocks shown in FIG. 34, theperformance in correcting a scratch extending in the longitudinaldirection of the track is similar to that exhibited when the sync blocksare arranged in the example shown in FIG. 33. However, according to thearrangement shown in FIG. 34, the error correcting performance is mosteffective for clogging on one side channel occurring during a readingoperation.

For example, when Reed-Solomon codes are interleaved on 16 planes over16 tracks, there are two approaches to arrange the sync blocks and toadd parities by the error code/ID adder 5. In one method, as shown inFIG. 35, the sync blocks are arranged as follows. The 16 planes areformed while error correcting codes are interleaved, and parities arethen added. Thereafter, the sync blocks are arranged in the order of thearrangement on the magnetic tape 21.

More specifically, in the example shown in FIG. 35, when the data outputfrom the video data compressor (MPEG encoder) 1 is temporally in theorder D0, D1, D1, D2, D3, and so on, the data input into a memory 91 aretemporally assigned to planes 91-1 through 91-16. In other words, dataD0 through D15 are sequentially disposed in the planes 91-1 through91-16, respectively. Then, the subsequent data D16 is again disposed inthe plane 91-1. In this manner, data are sequentially positioned in theplanes 91-1 through 91-16.

After the planes are formed in the memory 91, an outer parity (parityC2) is calculated and added for each of the planes 91-1 through 91-16 byan outer parity adder 92.

The data with the outer parities are then supplied to a memory 93. Inthe memory 93, the data is sequentially arranged in the same orderarranged by the video data compressor 1 (in the order D0, D1, D2, and soon), and 139 pieces of data (121 pieces of data and 18 parities) arestored for each of a first memory area 93-1 through a sixteenth memoryarea 93-16. That is, for example, data D0, D1, D2, . . . , D120 and thecorresponding parities P0, P1, . . . , P17 are stored in the firstmemory area 93-1. Data D121, D122, . . . , D241, and the correspondingparities are stored in the second memory area 93-2.

According to the priority concerning which type of error the errorcorrecting performance is used, the 16 data groups are read from thememory 93 according to either method shown in FIG. 33 or 34, and aresupplied to an inner parity adder 94. In the inner parity adder 94, aninner parity (parity C1) is added. Then, the order of the data outputfrom the video data compressor 1 can be rearranged to the order of dataon the magnetic tape 21. With this arrangement, a continuous error,which may occur during a reading operation, becomes temporallycontinuous when it is input into the video data decompressor 48. Thismethod is effective on occasions, such as when there are continuouserrors within a B picture. A B picture is not referred to by otherpictures (I picture and P picture) according to the MPEG method, andthus, errors occurring in a B picture do not travel to an I picture or aP picture. On the other hand, it is very likely that errors occur for asmall amount of data.

As another approach to arrange the sync blocks and to add parities, asshown in FIG. 36, after parities are added, the data are rearranged bybeing shuffled in the order of the arrangement on the magnetic tape 21.More specifically, as shown in FIG. 36, the data D0, D1, D2, and so on,output from the video data compressor 1 are assigned in units of 121data to 16 different planes in the temporal order in the memory 91. Forexample, the first data D0 through 121st data D120 are stored in thefirst memory area 91-1, and the 122nd data D121 through the 242nd dataD241 are stored in the second memory area 91-2. In the same manner, thesubsequent data are stored in the memory areas 91-3 through 91-16.

Upon completing the formation of the 16 planes in the memory 91, anouter parity is added for each plane by the outer parity adder 92. Thedata with the outer parities are then assigned to the first throughsixteenth groups in the memory 93 so that the distance between adjacentdata is set to be constant among the planes. For example, the data D0 isstored in the first memory area 93-1, and the subsequent data D1 isstored in the second memory area 93-2. Similarly, the data D15 is storedin the sixteenth memory area 93-16. Then, the 17th data D16 is againstored in the first memory area 93-1, and the 18th data D17 is stored inthe second memory area 93-2.

As described above, according to the priority concerning which type oferror the error correcting performance is used, the sixteen data groupsare read from the memory 93 group by group according to either methodshown in FIG. 33 or 34, and are supplied to the inner parity adder 94.An inner parity is added to each data by the inner parity adder 94. Thatis, an inner parity is added to the data and the outer parity stored inthe first memory area 93-1, and another inner parity is added to thedata and the outer parity stored in the second memory area 93-2. Thesame applies to the subsequent data and the outer parities.

In this manner, the order of the data output from the video compressor 1is rearranged to the order of the sync blocks on the individual planes.Thus, continuous errors may occur on the track during a readingoperation in the following manner. When the data is input into the videodata decompressor 48, it is very unlikely that errors continue in time,but errors may occur at regular intervals among 16 planes. In this case,in the MPEG method, errors occur over a plurality of pictures, and bycross-referring to pictures, an error may propagate more easily comparedto the method shown in FIG. 35. On the other hand, errors will seldomoccur for a small amount of data.

Accordingly, the arrangements of sync blocks on the magnetic tape 21 canbe classified into the following four types according to the resistanceto continuous errors and the distribution of uncorrectable errors:

(1) resistant to continuous errors caused by an extraneous substance onthe tape, and uncorrectable errors temporally concentrating on oneportion;

(2) resistant to continuous errors caused by an extraneous substance onthe tape, and uncorrectable errors being temporally distributed;

(3) resistant to continuous errors caused by clogging on one sidechannel, and uncorrectable errors temporally concentrating on oneportion; and

(4) resistant to continuous errors caused by clogging on one sidechannel, and uncorrectable errors being temporally distributed.

FIGS. 37 through 39 illustrate an example of the type (1) arrangement ofsync blocks when error correcting codes are interleaved on 16 planesover 16 tracks. In contrast, FIGS. 40 through 42 illustrate an exampleof the type (2) arrangement of sync blocks when error correcting codesare interleaved on 16 planes over 16 tracks.

In FIGS. 37 through 42, M_(i) (i=1, 2, . . . , 16) indicates the planenumber, D_(j) (j=1, 2, . . . ) represents sync block data, P_(k) (k=1,2, . . . ) designates a parity, and j and k represent serial numbers.

In the examples shown in FIGS. 37 through 42, outer parities (paritiesC2) are disposed toward the end of the track.

When Reed-Solomon codes are formed on 16 planes over 16 tracks andinterleaved under the above-described condition (1) or (2), continuouserrors extending over two tracks and ten sync blocks can be corrected,as shown in FIG. 43. Similarly, when Reed-Solomon codes are formed underthe above-described condition (3) or (4), continuous errors over twotracks and four sync blocks caused by clogging on one side channel canbe corrected, as shown in FIG. 44.

The resistance to continuous errors can be varied even by using the sameReed-Solomon codes. For example, FIGS. 45 and 46 illustrate an exampleof the arrangement of sync blocks in which Reed-Solomon codes areinterleaved on 12 planes over 12 tracks. FIGS. 47 and 48 illustrate anexample of the arrangement of sync blocks in which Reed-Solomon codesare interleaved on 8 planes over 8 tracks.

In the example shown in FIGS. 45 and 46, burst errors extending over onetrack and 77 sync blocks can be corrected, while clogging on one sidechannel for one track and 63 sync blocks can be corrected.

In contrast, in the example shown in FIGS. 47 and 48, burst errorsextending for one track and five syncs can be corrected, while cloggingon one side channel for one track and two sync blocks can be corrected.

FIGS. 49A, 49B, and 49C illustrate another example of the configurationof the main sector. As in the example shown in FIGS. 24A, 24B, and 24C,the length of the main sector is 111 bytes. However, the number of syncblocks is 141, and thus, the number of sync blocks forming the main datais increased to 123, which is greater than that shown in FIGS. 24Athrough 24C by two. The other configurations of this example are similarto those shown in FIGS. 24A through 24C.

FIG. 50 illustrates an example of a recording system of a magnetic taperecording/reading apparatus when the main sector is configured as shownin FIGS. 49A through 49C. A sync generator 7A is substituted for thesync ITI generator 7 shown in FIG. 3.

The sync generator 7A generates sync data to be added to the main data(FIGS. 49A through 49C) or the subcode (FIG. 25), and preamble andpostamble data. The other configurations are similar to those shown inFIG. 3.

FIG. 51 illustrates an example of the sector arrangement in each trackof the magnetic tape 21 shown in FIG. 50. The numbers of bitsrepresenting the lengths of the individual elements shown in FIG. 51 arenumbers after 24-25 conversion is performed. The length of one track is134975 bits when the rotary head 12 is rotated at a frequency of60×1000/1001 Hz, and is 134850 bits when the rotary head 12 is rotatedat a frequency of 60 Hz. The length of one track is equal to a portionof the magnetic tape 21 up to a winding angle of 174 degrees. Outsidethe one-track portion, a 1250-bit overwrite margin is formed forpreventing data from remaining recorded.

In FIG. 51, the rotary head 12 traces over the track from the left tothe right. At the head of the track, a 1800-bit preamble is disposed. Asin the postamble after the subcode sector shown in FIG. 8, in thispreamble shown in FIG. 51, data required for generating a clock, such asa combination of pattern A and pattern B shown in FIG. 26, is recorded.In pattern A and pattern B, “0”s and “1”s are inverted with respect toeach other. By suitably combining these patterns, the tracking patternsF0, F1, and F2 shown in FIGS. 5, 6, and 7, respectively, can beimplemented. The run pattern shown in FIG. 26 represents a pattern after24–25 conversion is performed by the 24-25 converter 6 shown in FIG. 50.

After the 1800-bit preamble, a 134850-bit main sector is disposed. Thestructure of the main sector is shown in FIG. 49A.

As shown in FIG. 49A, the main sector is formed of 141 sync blocks, andthe length of each sync block is 888 bits (111 bytes).

The first 123 sync blocks are each formed of a two-byte (16-bit) sync, athree-byte (24-bit) ID, 96-byte (768-bit) main data, and 10-byte(80-bit) parity C1. The syncs are generated by the sync generator 7A.The ID is added by the error code/ID adder 5.

When the main data is video data, it is supplied from the video datacompressor 1. When the main data is audio data, it is supplied from theaudio data compressor 2. When the main data is auxiliary data, it issupplied from the controller 13 via the terminal 3.

The parity C1 is calculated from the ID and the main data for each syncblock by the error code/ID adder 5, and is then added.

Among the 141 sync blocks, the last 18 sync blocks are each formed of async, an ID, parity C2, and parity C1. The parity C2 is calculated basedon the main data in the longitudinal direction in FIG. 49A. Thiscalculation is performed in the error code/ID adder 5.

The total amount of data of the main sector is 888 bits×141 syncblocks=125208 bits, and becomes 130425 bits after 24-25 conversion. Themaximum data rate when the rotary head 12 is rotated in synchronizationwith 60 Hz is substantially 768 bits×123 sync blocks×10 tracks×30Hz=28.339 Mbps. This bit rate is sufficient to record MP@HL-compressedor MP@H-14-compressed HD video data, audio compressed data, auxiliarydata, and search video data.

Subsequent to the main data, a 1250-bit subcode sector is disposed. Theconfiguration of the subcode sector is shown in FIG. 25.

After the subcode sector, a postamble is located. The postamble, as wellas the preamble, can be recorded by a combination of pattern A andpattern B shown in FIG. 26. The length of the postamble is 1500 bitswhen the rotary head 12 is rotated in synchronization with 60×1000/1001Hz, and is 1375 bits when the rotary head 12 is rotated insynchronization with 60 Hz.

The operation of the recording system shown in FIG. 50 is similar tothat of the counterpart shown in FIG. 3, and an explanation thereof willthus be omitted.

FIG. 52 illustrates an example of the configuration of a reading systemfor reading the data recorded on the magnetic tape 21 shown in FIG. 50.This reading system is similar to that shown in FIG. 27, except that,instead of the sync ITI detector 44 shown in FIG. 27, a sync detector44A is used.

The sync detector 44A detects the sync of each sync block of the mainsector shown in FIG. 49A and the sync of each subcode sync block of thesubcode sector shown in FIG. 25 from the demodulated data output fromthe demodulator 43, and supplies the detected syncs to the errordetector/ID corrector 46.

The operation of the reading system shown in FIG. 52 is similar to thatof the counterpart shown in FIG. 27, and an explanation thereof willthus be omitted.

For the main sector shown in FIG. 49A, a Galois field GF (2⁸)Reed-Solomon code (141, 123, 19) is used as the outer error correctingcode. In this case, the recording bit rate of the main data is 768bits×123 sync blocks×10 tracks×30 Hz is 28.339 Mbps.

According to the configuration shown in 49A, as well as in that shown inFIG. 24A, bit errors caused by a scratch extending for a maximum of 650μm in the longitudinal direction of the track can be corrected.Additionally, by interleaving outer error correcting codes over aplurality of tracks, for example, 16 tracks, continuous errors for twotracks can be corrected.

FIGS. 53 through 55 illustrate an example of the arrangement of syncblocks on the magnetic tape 21 in which error correcting codes areinterleaved on 16 planes over 16 tracks according to the method shown inFIG. 33.

FIGS. 56 through 58 illustrate an example of the arrangement of syncblocks on the magnetic tape 21 in which error correcting codes areinterleaved on 16 planes over 16 tracks according to the method shown inFIG. 34.

Parity C2 may be disposed at the end of the track, as shown in FIG. 49B,or may be divided and disposed at the head and the end of the track, asshown in FIG. 49C.

FIG. 59A illustrates still another example of the configuration of themain sector. In this example, the length of one sync block is 114 bytes,and 135 sync blocks form the main sector. Among the 135 sync blocks, 118sync blocks serve as the main data, and 17 sync blocks serve as parityC2.

In each sync block, the length of the sync is two bytes, and the lengthof the ID is three bytes. The length of the main data is 99 bytes, andthe length of parity C1 is 10 bytes. As the outer error correcting code,a Galois field (2⁸) Reed-Solomon code (135, 118, 18) is used. With thisarrangement, bit errors caused by a scratch extending for a maximum ofabout 630 μm in the longitudinal direction of the track can becorrected. Additionally, by interleaving the outer error correctingcodes over a plurality of tracks, for example, 16 tracks, on themagnetic tape 21, continuous errors over two tracks can be corrected.

The error correcting performance of the example shown in FIG. 59A isslightly lower than that of the example shown in FIG. 24A. On the otherhand, the recording rate of the main data can be improved to 792bits×118 sync blocks×10 tracks×30 Hz=28.0368 Mbps.

As in the example shown in FIGS. 24B and 24C, parity C2 may be locatedat the end of the track, as shown in FIG. 59B, or may be divided andlocated at the head and the end of the track, as shown in FIG. 59C.

FIG. 60 illustrates an example of the sector arrangement in each trackwhen the main sector is formed as shown in FIG. 59. The basicconfiguration of the sector arrangement is similar to that shown in FIG.8. Accordingly, the recording and reading operation can be performed bythe recording system shown in FIG. 3 and the reading system shown inFIG. 27. However, in the example shown in FIG. 60, the length of themain sector is 128250 bits (=114×8×135×25/24 bits), and the length ofthe postamble is 1875 bits.

FIGS. 61A through 61C illustrate a further example of the configurationof the main sector. As in the example shown in FIGS. 59A through 59C,the length of one sync block is 114 bytes. The number of sync blocks ofthe main data in one track is 118, and that of the parity C2 is 17.Accordingly, as the outer error correcting code, a Galois field (2⁸)Reed-Solomon code (135, 118, 18) is used.

In this example, the length of the main data of one sync block is 97bytes, and that of the parity C1 is 12 bytes. With this configuration,it is possible to correct bit errors caused by a scratch extending for amaximum of 630 μm in the longitudinal direction of the track.Additionally, by interleaving outer error correcting codes over aplurality of tracks, for example, 16 tracks, on the magnetic tape 21,continuous errors over two tracks can be corrected. The error correctingperformance of the inner error correcting codes is improved over theexample shown in FIGS. 24A through 24C. The probability that the data isnot correctly decoded is indicated by curve A in FIG. 62. In comparisonwith curve A shown in FIG. 30, the probability that the data is notcorrectly decoded is decreased.

The number of parity bits is also increased by 16 bits compared with theexample shown in FIGS. 24A through 24C. Accordingly, the probability QINthat the data is erroneously corrected is expressed by the followingequation.QIN=1.3E ⁻²⁹However, in comparison with the example shown in FIGS. 24A through 24C,the error correcting performance is improved with an impairment of therecording rate, which results in 776 bits×118 sync blocks×10 tracks×30Hz=27.4704 Mbps.

As is seen from the foregoing description, when recording or readingMPEG-compressed data as discussed above, the following advantages can beoffered over the DV format.

In case of the occurrence of spontaneous clogging generated during arecording operation (recording errors), about one track of such an errorcan be corrected when error correcting codes are interleaved on eightplanes over eight tracks, and about two tracks of such an error can becorrected when error correcting codes are interleaved on 16 planes over16 tracks. The resistance to reading errors caused by splices on therecorded tape can be enhanced. That is, if a new track is spliced tooclose to the previous track, the previous track becomes smaller than itshould be. Such an error can be corrected. Also, the error resistance toa scratch in the longitudinal direction of tape is higher than that ofthe DV format by about 1.8 times or greater. The ID is included togetherwith the main data in Reed-Solomon codes, and thus, the reliability ofcontinuity checking of the sync block numbers and track numberscontained in the ID can be improved. Accordingly, the probability thatdata cannot be correctly decoded during a reading operation is muchlower than that of the DV format. The length of the sync block is 111bytes or 114 bytes, which is compatible with the length of a transportstream in the MPEG method when it is disposed in the sync blocks. Thus,the reading and recording of transport streams transferred via a digitalinterface, which is one of the standard formats, can be easilyperformed. Additionally, since 24-25 conversion used in the DV format isalso applicable to the magnetic tape format of the present invention,the corresponding system can be easily constructed based on the DVsystem.

It can thus be understood that the present invention is effective as oneformat for recording and reading MPEG compressed data on and from, notonly digital video cassettes, but also tape media.

The above-described series of processing may be executed by hardware orsoftware. If software is used, it can be installed from a recordingmedium into a computer which contains special hardware integrating thecorresponding software program or into a computer, for example, ageneral-purpose computer, which executes various functions by installingvarious programs.

Such a recording medium may be formed of a package medium, which isdistributed to the user separately from the magnetic taperecording/reading apparatus, such as a magnetic disk 31 (including afloppy disc), an optical disc 32 (including compact disc read onlymemory (CD-ROM) and a digital versatile disk (DVD)), a magneto-opticaldisk 33 (including an mini disk (MD)), or a semiconductor memory 34. Therecording medium may also be formed of a ROM or a hard disk on which theprogram is recorded, which can be provided to the user while beinginstalled in the magnetic disc recording/reading apparatus.

It is not essential that the steps forming the program recorded on arecording medium be executed chronologically according to the orderdiscussed in this specification. Alternatively, they may be executedconcurrently or individually.

1. A magnetic tape recording apparatus for recording digital data ontracks of a magnetic tape by using a rotary head, comprising: formattingmeans for adding error correcting code to each of first group dataincluding video data, audio data, or search data, and second group dataincluding subcode data related to said first group data, and forformatting said first group data and said second group data so that saidfirst group data and said second group data are continuously disposed onthe tracks of said magnetic tape; and supply means for supplying thedata formatted by said formatting means to said rotary head so as torecord the data on said magnetic tape, wherein: said formatting meanscontinuously disposes sync blocks on each of said tracks, each of saidsync blocks having a predetermined number of bytes; said sync blockscomprising second sync blocks each second sync block consisting of adetection pattern for detecting the sync block, identificationinformation for identifying the sync block, main data, and inner errorcorrecting code added to said identification information and said maindata, and a remaining quantity of sync blocks each consist of thedetection pattern, identification information, an outer error correctingcode, and the inner error correcting code; and said outer errorcorrecting code is provided for each group of the sync blocks obtainedby dividing third sync blocks contained in a predetermined quantity oftracks by a predetermined quantity of planes; and said sync blocks arearranged on said magnetic tape so that a distance between the syncblocks belonging to the identical plane is constant among the planes. 2.A magnetic tape recording apparatus according to claim 1, wherein thevideo data is high definition video data compressed by an MP@HL orMP@H-14 method.
 3. A magnetic tape recording method for use in amagnetic tape recording apparatus for recording digital data on tracksof a magnetic tape by using a rotary head, said magnetic tape recordingmethod comprising: a formatting step of adding error correcting code toeach of first group data including video data, audio data, or searchdata, and second group data including subcode data related to said firstgroup data, and formatting said first group data and said second groupdata so that said first group data and said second group data arecontinuously disposed on the tracks of said magnetic tape; and a supplystep of supplying the data formatted in said formatting step to saidrotary head so as to record the data on said magnetic tape, wherein:said formatting step continuously disposes sync blocks on each of saidtracks, each of said sync blocks having a predetermined number of bytes;said sync blocks comprising second sync blocks each consisting of adetection pattern for detecting the sync block, identificationinformation for identifying the sync block, main data, and inner errorcorrecting code added to said identification information and said maindata, and a remaining quantity of the sync blocks each consist of thedetection pattern, the identification information, outer errorcorrecting code, and the inner error correcting code; and said outererror correcting code is provided for each group of the sync blocksobtained by dividing third sync blocks contained in a first quantity oftracks by a first quantity of planes; and said sync blocks are arrangedon said magnetic tape so that a distance between the sync blocksbelonging to the identical plane is constant among the planes.
 4. Acomputer readable medium having stored a computer readable programexecuted by a computer for controlling a magnetic tape recordingapparatus to perform a method to record digital data on tracks of amagnetic tape by using a rotary head, the method comprising: aformatting step of adding error correcting code to each of first groupdata including video data, audio data, or search data, and second groupdata including subcode data related to said first group data, andformatting said first group data and said second group data so that saidfirst group data and said second group data are continuously disposed onthe tracks of said magnetic tape; and a supply step of supplying thedata formatted in said, formatting step to said rotary head so as torecord the data on said magnetic tape, wherein: said formatting stepcontinuously disposes sync blocks on each of said tracks, each of saidsync blocks having a predetermined number of bytes; said sync blockscomprising second sync blocks each second sync block consisting of adetection pattern for detecting the sync block, identificationinformation for identifying the sync block, main data, and inner errorcorrecting code added to said identification information and said maindata, and remaining quantity of sync blocks each consist of thedetection pattern, the identification information, outer errorcorrecting code, and the inner error correcting code; and said outererror correcting code is provided for each group of the sync blocksobtained by dividing third sync blocks contained in a first number oftracks by a first number of planes; and said sync blocks are arranged onsaid magnetic tape so that a distance between the sync blocks belongingto the identical plane is constant among the planes.
 5. A magnetic taperecording apparatus for recording digital data on tracks of a magnetictape by using a rotary head, comprising: formatting means for addingerror correcting code to each of first group data including video data,audio data, or search data, and second group data including subcode datarelated to said first group data, and for formatting said first groupdata and said second group data so that said first group data and saidsecond group data are continuously disposed on the tracks of saidmagnetic tape; and supply means for supplying the data formatted by saidformatting means to said rotary head so as to record the data on saidmagnetic tape, wherein: said formatting means continuously disposes syncblocks on each of said tracks, each of said sync blocks having apredetermined number of bytes; said sync blocks comprising second syncblocks each second sync block consisting of a detection pattern fordetecting the sync block, identification information for identifying thesync block, main data, and inner error correcting code added to saididentification information and said main data, and a quantity ofremaining sync blocks each consist of the detection pattern, theidentification information, outer error correcting code, and the innererror correcting code; and said outer error correcting code is providedfor each group of the sync blocks obtained by dividing third sync blockscontained in a first quantity of tracks by a first quantity of planes;and said sync blocks are arranged on said magnetic tape so that adistance between the sync blocks belonging to the identical plane isconstant among the planes.
 6. A magnetic tape recording apparatusaccording to claim 5, wherein the video data is high definition videodata compressed by an MP@HL or MP@H-14 method.
 7. A magnetic taperecording method for use in a magnetic tape recording apparatus forrecording digital data on tracks of a magnetic tape by using a rotaryhead, said magnetic tape recording method comprising: a formatting stepof adding error correcting code to each of first group data includingvideo data, audio data, or search data, and second group data includingsubcode data related to said first group data, and formatting said firstgroup data and said second group data so that said first group data andsaid second group data are continuously disposed on the tracks of saidmagnetic tape; and a supply step of supplying the data formatted in saidformatting step to said rotary head so as to record the data on saidmagnetic tape, wherein: said formatting step continuously disposes syncblocks on each of said tracks, each of said sync blocks having apredetermined number of bytes; said sync blocks comprising second syncblocks each second sync block consisting of a detection pattern fordetecting the sync block, identification information for identifying thesync block, main data, and inner error correcting code added to saididentification information and said main data, and a quantity ofremaining sync blocks each consist of the detection pattern, theidentification information, outer error correcting code, and the innererror correcting code; and said outer error correcting code is providedfor each group of the sync blocks obtained by dividing third sync blockscontained in a first quantity of tracks by a first quantity of planes;and said sync blocks are arranged on said magnetic tape so that adistance between the sync blocks belonging to the identical plane isconstant among the planes.
 8. A computer readable medium having stored acomputer readable program executed by a computer to control a magnetictape recording apparatus to perform a method to record digital data ontracks of a magnetic tape by using a rotary head, the method comprising:a formatting step of adding error correcting code to each of first groupdata including video data, audio data, or search data, and second groupdata including subcode data related to said first group data, andformatting said fast group data and said second group data so that saidfirst group data and said second group data are continuously disposed onthe tracks of said magnetic tape; and a supply step of supplying thedata formatted in said formatting step to said rotary head so as torecord the data on said magnetic tape, wherein: said formatting stepcontinuously disposes sync blocks on each of said tracks, each of saidsync blocks having a predetermined number of bytes; said sync blockscomprising second sync blocks each second sync block consisting of adetection pattern for detecting the sync block, identificationinformation for identifying the sync block, main data, and inner errorcorrecting code added to said identification information and said maindata, and a remaining quantity of sync blocks each consist of thedetection pattern, the identification information, outer errorcorrecting code, and the inner error correcting code; and said outererror correcting code is provided for each group of the sync blocksobtained by dividing third sync blocks contained in a first quantity oftracks by a first quantity of planes; and said sync blocks are arrangedon said magnetic tape so that a distance between the sync blocksbelonging to the identical plane is constant among the planes.
 9. Amagnetic tape recording apparatus for recording digital data on tracksof a magnetic tape by using a rotary head, comprising: formatting meansfor adding error correcting code to each of first group data includingvideo data, audio data, or search data, and second group data includingsubcode data related to said first group data, and for formatting saidfirst group data and said second group data so that said first groupdata and said second group data are continuously disposed on the tracksof said magnetic tape; and supply means for supplying the data formattedby said formatting means to said rotary head so as to record the data onsaid magnetic tape, wherein: said formatting means continuously disposessync blocks on each of said tracks, each of said sync blocks having apredetermined number of bytes; said sync blocks comprising second syncblocks each second sync block consisting of a detection pattern fordetecting the sync block, identification information for identifying thesync block, main data, and inner error correcting code added to saididentification information and said main data, and a quantity ofremaining sync blocks each consist of the detection pattern, theidentification information, outer error correcting code, and the innererror correcting code; and said outer error correcting code is providedfor each group of the sync blocks obtained by dividing third sync blockscontained in a first quantity of tracks by a first quantity of planes;and said sync blocks are arranged on said magnetic tape so that adistance between the sync blocks belonging to the identical plane isconstant among the planes.
 10. A magnetic tape recording apparatusaccording to claim 9, wherein the video data is high definition videodata compressed by an MP@HL or MP@H-14 method.
 11. A magnetic taperecording method for use in a magnetic tape recording apparatus forrecording digital data on tracks of a magnetic tape by using a rotaryhead, said magnetic tape recording method comprising: a formatting stepof adding error correcting code to each of first group data includingvideo data, audio data, or search data, and second group data includingsubcode data related to said first group data, and formatting said firstgroup data and said second group data so that said first group data andsaid second group data are continuously disposed on the tracks of saidmagnetic tape; and a supply step of supplying the data formatted in saidformatting step to said rotary head so as to record the data on saidmagnetic tape, wherein: said formatting step continuously disposes syncblocks on each of said tracks, each of said sync blocks having apredetermined number of bytes; said sync blocks comprising second syncblocks each second sync block consisting of a detection pattern fordetecting the sync block, three-byte identification information foridentifying the sync block, main data, and inner error correcting codeadded to said identification information and said main data, and aquantity of remaining sync blocks each consist of the two-byte detectionpattern, the three-byte identification information, outer errorcorrecting code, and the inner error correcting code; and said outererror correcting code is provided for each group of the sync blocksobtained by dividing third sync blocks contained in a first quantity oftracks by a first quantity of planes; and said sync blocks are arrangedon said magnetic tape so that a distance between the sync blocksbelonging to the identical plane is constant among the planes.
 12. Acomputer readable medium having stored a computer readable programexecuted by a computer to control a magnetic tape recording apparatus toperform a method to record digital data on tracks of a magnetic tape byusing a rotary head, the method comprising: a, formatting step of addingerror correcting code to each of first group data including video data,audio data, or search data, and second group data including subcode datarelated to said first group data, and formatting said first group dataand said second group data so that said first group data and said secondgroup data are continuously disposed on the tracks of said magnetictape; and a supply step of supplying the data formatted in saidformatting step to said rotary head so as to record the data on saidmagnetic tape, wherein: said formatting step continuously disposes syncblocks on each of said tracks, each of said sync blocks having apredetermined number of bytes; said sync blocks comprising second syncblocks each second sync block consisting of a two-byte detection patternfor detecting the sync block, three-byte identification information foridentifying the sync block, main data, and inner error correcting codeadded to said identification information and said main data, and aquantity of remaining sync blocks each consist of the two-byte detectionpattern, the three-byte identification information, outer errorcorrecting code, and the inner error correcting code; and said outererror, correcting code is provided for each group of the sync blocksobtained by dividing third sync blocks contained in a first quantity oftracks by a first quantity of planes; and said sync blocks arranged onsaid magnetic tape so that a distance between the sync blocks belongingto the identical plane is constant among the planes.
 13. A magnetic taperecording apparatus for recording digital data on tracks of a magnetictape by using a rotary head, comprising: formatting means for addingerror correcting code to each of first group data including video data,audio data, or search data, and second group data including subcode datarelated to said first group data, and for formatting said first groupdata and said second group data so that said first group data and saidsecond group data are continuously disposed on the tracks of saidmagnetic tape; and supply means for supplying the data formatted by saidformatting means to said rotary head so as to record the data on saidmagnetic tape, wherein: said formatting means continuously disposes syncblocks on each of said tracks, each of said sync blocks having apredetermined number of bytes; said sync blocks comprising second syncblocks each second sync block consisting of a two-byte detection patternfor detecting the sync block, three-byte identification information foridentifying the sync block, main data, and inner error correcting codeadded to said identification information and said main data, and aquantity of remaining sync blocks each consist of the two-byte detectionpattern, the three-byte identification information, outer errorcorrecting code, and the inner error correcting code; and said outererror correcting code is provided for each group of the sync blocksobtained by dividing third sync blocks contained in a first quantity oftracks by a first quantity of planes; and said sync blocks arranged onsaid magnetic tape so that a distance between the sync blocks belongingto the identical plane is constant among the planes.
 14. A magnetic taperecording apparatus according to claim 13, wherein the video data ishigh definition video data compressed by an MP@HL or MP@H-14 method. 15.magnetic tape recording method for use in a magnetic tape recordingapparatus for recording digital data on tacks of a magnetic tape byusing a rotary head, said magnetic tape recording method comprising: aformatting step of adding error correcting code to each of first groupdata including video data, audio data, or search data, and second groupdata including subcode data related to said first group data, andformatting said first group data and said second group data so that saidfirst group data and said second group data are continuously disposed onthe tracks of said magnetic tape; and a supply step of supplying thedata formatted in said formatting step to said rotary head so as torecord the data on said magnetic tape, wherein: said formatting stepcontinuously disposes sync blocks on each of said tracks, each of saidsync blocks having a predetermined number of bytes; said sync blockscomprising second sync blocks each second sync block consisting of atwo-byte detection pattern for detecting the sync block, three-byteidentification information for identifying the sync block, main data,and inner error correcting code added to said identification informationand said main data, and a quantity of remaining sync blocks each consistof the two-byte detection pattern, the three-byte identificationinformation, outer error correcting code, and the inner error correctingcode; and said outer error correcting code is provided for each group ofthe sync blocks obtained by dividing third sync blocks contained in afirst quantity of tracks by a first quantity of planes; and said syncblocks arranged on said magnetic tape so that a distance between thesync blocks belonging to the identical plane is constant among theplanes.
 16. A computer readable medium having stored a computer readableprogram executed by a computer to control a magnetic tape recordingapparatus to perform a method to record digital data on tracks of amagnetic tape by using a rotary head, the method comprising: aformatting step of adding error correcting code to each of first groupdata including video data, audio data, or search data, and second groupdata including subcode data related to said first group data, andformatting said first group data and said second group data so that saidfirst group data and said second group data are continuously disposed onthe tracks of said magnetic tape; and a supply step of supplying thedata formatted in said formatting step to said rotary head so as torecord the data on said magnetic tape, wherein: said formatting stepcontinuously disposes sync blocks on each of said tracks, each of saidsync blocks having a predetermined number of bytes; said sync blockscomprising second sync blocks each second sync block consisting of atwo-byte detection pattern for detecting the sync block, three-byteidentification information for identifying the sync block, main data,and inner error correcting code added to said identification informationand said main data, and a quantity of remaining sync blocks each consistof the two-byte detection pattern, the three-byte identificationinformation, outer error correcting code, and the inner error correctingcode; and said outer error correcting code is provided for each group ofthe sync blocks obtained by dividing third sync blocks contained in afirst quantity of tracks by a first quantity of planes; and said syncblocks arranged on said magnetic tape so that a distance between thesync blocks belonging to the identical plane is constant among theplanes.